Change-speed gearing



y 9 w. R. GRISWOLD 2,201,169

CHANGE-SPEED GEARING Filed Feb. 2, 1957 4 Sheets-Sheet 1 y 1940- w. R. GRISWOLD 2,201,169 I CHANGE-SPEED GEARING I Filed Feb. 2, 1937 4 Sheets-Sheet 3 E .5 ["1 i "Hwy-"Hill May 21, 1940. w. R. GRISWOLD 2,201,169

CHANGE-SPEED GEARING Filed Feb. 2, 1957 4 Sheets-Sheet 4 Ti .3 I5 22 Patented May 21, 1940 a 220L169 .UNlTED STATES PATENT OFF-ICE Walter B. Griawold,'Detroit, Mich, alsignor to Packard Motor Car Company, Detroit, Mlcia, a corporation of Michigan Application February 2, 1937, Serial No. 128,681 6 Claims. (Cl. 192-53) This invention relates to change-speed gearing ments which are arranged for selective meshing and is particularly concerned with improvements engagement by the first element, and a device in variable speed transmission gearing for motor which is caused to assume, during lack of proper vehlgles, synchronization, a position in which relative In the operation of motor vehicles, it is requisite movement of the elements to intermeshing posi- 5 to smooth gear changing that the gears or positive tion is retarded, opposed, or prevented and which clutch elements which are to be meshed be may assume, when proper synchronization h brought to the same or substantially the same been establishecL'a second position in which fairly peripheral speed before engagement of the gear free movement of the elements to intermeshing teeth. Thus after disconnection of the vehicle relation is permitted. m clutch and the previously meshed gears of a con- A further object of the invention is to provide ventional transmission, the operator must either a motor vehicle transmission having an improved t fgr more rapidly moving gear le nt to device for synchronizing the toothed elements in lose speed, or in some instances must accelerate the gear train, which device is simple and-effec- 5 a more slowly moving gear by reconnecting it to t ve, e iable in operation, and which will act to the engine through the clutch. These maneuvers nimi the il y f lashin of the toothed require considerable measure of in on th part elements or of the selecting devices therefor durof the operator and also prevent the free and s Selection of a desired speed ratio. rapid changing from one gear train to another Further objects and features of the invention as the contingencies of vehicle operation may will be apparent m t e following description, 20 dictate, so that gear changing has come to be tnken in connection i e accompanying considered as perhaps the most diflicult task w s in whichincident to the operation of a motor vehicle. Figure 1 is a longitudinal vertical sectional view To assist t operator in making m and through a motor vehicle transmission to which as quiet shifts, it is now common practice to synthe invention may be readily applied;

chronize the gears or toothed clutch elements to Figure 2 is an exploded P p c V P y be meshed by various means, for example friction in Section, Of the ynchroni ing device shown in clutches, the latter being engaged immediately Figure prior to the meshing of the two rotating elements gure 3 is a sectional view on the diameter of no for the purpose of bringing them to the same one of the ta e e ents shown in Figure 2: rotational (or peripheral) speed. However, by re 4 is a side elevation of another of the reason of inexperience or undue haste the driver elements shown in Figure 2, illustrated in position frequently effects meshing of the cooperating eleon its supporting shaft; ments without permitting sufficient time to elapse Figure 5 is a fragmentary sectional view taken 2.3 to enable the elements to acquire the same speed, substantially on the line 5-4 of Figure '7; and as a result the elements clash and are thus Figure 6 is a vertical sectional view through subject to excessive wear or premature breakage. certain toothed elements and the synchronizing It is therefore one of the principal objects of device shown in Figure 1; the invention to provide means for synchronizing Figure 7 is a sectional view taken substantially toothed elements prior to the meshing thereof on the line 1-7 of Figure 6; which is so constructed as to ensure reasonably Figure 8 is a fragmentary Sectional V ew, Suhsatisfactory synchronization before the elements n i lly enlarged, Of a detail h wn in Figure 6; are actually brought into meshing engagement. Figure 9 is a vertical sectional view of a modified To accomplish this purpose the invention contemf rm 0! yn r nizing device and associated 43 plates either positive retention of the elements in toothed elements; non-meshing relationship until the correct rela- Figures 10 and 11 re end and side elevations tive speeds of rotation are established or yielding resp iv ly 1 he Synchronizing dev e shown opposition to the relative movement of the elen Figure h Outer el n being tted; ments toward intermeshing position such as to Fi ure 12 is a fragmentary pe v View 01 render difficult the meshing of the elements prior one of the e e e s o t e dev ce shown in Fi to the establishment of proper relative speeds. ure nd More specifically it is an object of the invention Figure 13 is a gm n ary vertical sectional to provide, in a transmission gearing for motor iew cor esp di g o Figure 6 but i ratin a vehicles, a device for synchronizing an intermedislightly modified form of construction. ate element with either of two cooperating ele- For convenience in illustrating the invention,

reference is made to the accompanying drawings and specific language is employed to describe the same. It will nevertheless be appreciated that various modifications and alterations of the devices illustrated would readily occur to one skilled in the art and that no limitation of the invention is intended by the use of detailed language. It will also be apparent that many of the features of the invention may be used either separately or conjointly and are applicable to other mechanisms than the transmission gearing in connection with which they are illustrated herein. Thus the gearing selected for illustration is of the so-called slidable key type in which coop-. crating toothed elements having internal and external teeth respectively are meshed or clutched together, but it will be noted that the synchronizing device described herein may be employed in transmissions of the slidable gear type in which two externally toothed elements are brought into meshing engagement while rotating at substantially the same linear speed. Again, while the synchronizing device shown herein is particularly adapted for the selective coupling of either of two adjacent toothed elements to a shaft, the device may be employed to connect only one element to a shaft or to bring only two gears into meshing relation.

For convenience, mention is made 1 herein of the synchronization and of the synchronous movement of two rotating elements. It will be appreciated that by synchronous rotation of coaxial toothed elements or clutches, reference is made to rotation of such elements at the same angular speed; as applied to externally toothed intermeshing elements or gears, or to a pair of cooperating externally and internally toothed elements of different diameter, synchronous rotation is such relative rotation as will give the same linear speed of the cooperating toothed portions of the two elements.

The transmission mechanism selected for the purpose of illustrating the invention is similar in all essential details to that shown in the prior patent to Vincent 1,901,713, granted .March 14, 1933, but the invention is of course not restricted to use with such mechanism. The gearing train is more or less conventional and includes a driving shaft I4 and a driving gear l5 having a toothed clutch portion l6 formed integrally therewith, gear l5 meshing with a gear i3 on an idler shaft IS. A second gear 20, mounted on the idler shaft and rotating with the gear i8, meshes with a gear 22, which is provided with a toothed clutch portion 2|. The gear 22 is freely rotatable on a driven shaft 23, which is in turn journalled as indicated at 24 within the gear 15 and driving shaft ll. The shafts l4 and 23 are journalled in and at opposite ends of the transmission housing 25 and are thereby supported in coaxial relation. Additional gears for securing further speeds are also illustrated in the drawings,

but are unnecessary to an understanding of the instant invention.

A synchronizing device indicated generally at 28, is carried on the driven shaft 23 intermediate the clutch elements l3 and 2| and is so constructed as to be capable of selectively coupling either the gear l5 or the gear 22 to the driven shaft 23, whereby the driven shaft 23 may be rotated either at the speed of rotation of the driving the idler shaft l9 and gears l3 and 20, by coupling of the gear 22 thereto. This type of transmission -to the driven shaft 23 and an annular element 32 which 'is in turn splined to the element 30. The splined connection between the elements and 32 comprises internal teeth ll on the latter and external teeth 35 on the former, the teeth 34 being also adapted for selective meshing relation with the teeth of the clutch portions l3 and 2| of the adjacent gears l5 and 22. A plurality of detents 31, urged radially outward by coil springs 33, are received in recesses 33 in the peripheral portion of the element 30 and are arranged to engage in relatively shallow pockets formed in the teeth 34 and disposed substantially in the median plane of the element 32. when the detents are thus seated, it will be appreciated that the elements 30 and 32, are yieldingly locked against relative axial displacement. Thus when the element 32 is displaced to either the right or the left from the position in which it is shown in Figure 6 of the drawings, for instance by means of a conventional shifter fork l2 engaging an annular groove 43 in the periphery of the element 32, the element 30 will tend to move axially therewith on the shaft 23 to engage and render operative either of two synchronizing clutches which are hereinafter more particularly described. Continued movement of the element 32, however, will tend to force the detents 31 out of the shallow pockets 40 in the element 32 against the action of the coil springs 38, and the element 32 will slide axially on the element 30 to engage either the clutch portion l6 of the gear II or the clutch portion 2| of the gear 22, depending on the direction of axial displacement, whereby either the gear I 5 or the gear 22 will be positively clutched to the driven shaft 23.

The cooperating members of the synchronizing clutch acting between the gear I! and the element 30 are preferably of the frictional type and may comprise a laterally directed annulus 44 formed integrally with the gear l5 and provided with an external conical clutch surface 45, and an annular member 41 carried by the element 30 and having a complementary internal conical surface 48 for engagement therewith. The surface 48 of the annular member 41 may be scored or grooved internally as indicated more particularly in Figure 8, and is secured, for example by shrinking, within an annular element 50, the latter having an inwardly directed radial flange 5i and a plurality of circumferentially spaced, outwardly directed segmentsformed with teeth 52. To further ensure rigid connection between the member 41 and the element 50. the latter may be provided with a plurality of circumferentially spaced apertures 53 into which the member 41 may be pressed.

Similarly the gear 22 is provided with a laterally directed annulus 55 which is formed to provide a conical clutch surface 33 which may cooperate with the complementary clutch surface ,58 formed on an annular element 59, the latter being shrunk within an annular element 30 which is formed to provide a plurality of circumferentially spaced, outwardly directed segments having teeth BI, and an annular inwardly directed radial flange 62. The flanges 5| and 62 of the annular elements 50 and are rigidly secured aaon co in spaced relation and in position at either side and 4| to an extent sufficient to permit slight rotative movement thereof as a unit with respect to the element 30. The pins 84 extend through circumferentially spaced apertures CI in the element 32, these apertures being of larger diameter than the pins to permit the slight relative rotative movement of the elements 20 and '0 hereinbei'ore referred to.

It will be observed that certain of they teeth 34 on the element 32 and of the teeth on the element 20 are of shorter length than the remainder and from Figure 2 of the drawings it will be noted that the circumferentially spaced teeth 52 and ii of the annular elements and iii are positioned so as to lie adjacent to these shorter teeth 24 and 28. When the teeth 52 and ii are positioned in alignment with the adjacent teeth 35, the element 82 is slidable freely on the element 20 in either direction from the neutral position in which it is shown in Figure 6 into cooperative engagement with either of the toothed clutch portions i6 and 2| of the gears II and 22. When, however, as the result of slight rotation of the elements Bil and I in either direction, the teeth 52 and II are out of alignment with the adjacent teeth 25, the teeth 34 on the annular element 32 will abut the teeth 52 and I to prevent axial displacement of the element 22 on the element 30 from the neutral position in which it is shown in Figure 6.

The operation of the device will now be apparent. Assuming that it is desired to couple the gear I! to the shaft 23, the shifter fork 42 is displaced toward the left from the position shown in Figures 1 and 6, for example, by manipulation of the conventional gear shift lever 4i, and the element 32 is displaced toward the left, carrying therewith the element 30 by reason of the action of the spring pressed detents 21, thus engaging the cooperating friction clutch surfaces and 48.- The engagement of these surfaces not only tends to establish the same speed of rotation in the element 30 and'the gear IE, but serves also to rotate the elements and 60 with respect to the element 30 so that the teeth 52 are displaced from alignment with the adjacent teeth 25 on the periphery of the element 20. Thus when the ends of the teeth 34 engage the adjacent ends of the teeth 52, the element 22 can be displaced no further to the left, except by the use of excessive force, and the operator is compelled to delay the completion of the shifting operation until the element 30 and the gear ii are rotating at the same or substantially the same speed. He will then be able to further displace the element 32 toward the left, the elements 50 and Bi) being rotated slightly by the camming action of the teeth 34 on the teeth 52 which results in re-establishment of the alignment of the'teeth 52 with the adjacent teeth 25, the cooperating ends of the teeth 34 and 52 being pointed to facilitate this action and also chamfered. When this alignment is accomplished, the element 32 may be freely moved to the left into cooperative clutching engagement with the toothed portion it of the gear l5.

The construction is of course duplicated at the opposite side of the elements 30 and 22 so that on displacement of the element 22 to the right, the operator is compelled to delay the com- By varying the angle of chamfer on the crating ends of the teeth 34 on the element 22 pletion of the shifting movement until the elements to be coupled have been properly or at least substantially synchronized.

coopand the teeth 52 and BI, the shifting of the element )2 into positive clutching position with either of the'clutch portions I. or 2i, may be rendered either more or less difficult. but in any event it will be appreciated that positive clutching can be 'ei'i'ected, prior to the complete synchrcnization of the cooperating clutch elements, only by the application of sumcient force to overcome the torque applied to the element 20 by the synchronizing friction clutch.

Referring now to the form of the invention shown in Figures 9 to 12 inclusive of the drawings, in which elements similar to those hereinbefore referred to are designated by similar reference numerals, it will be observed that the gears I 5 and 22 may be selectively clutched to the shaft 23 by the operation of an intermediate synchronizing device indicated generally at 24. This synchronizing device comprises an annular element 10, which is splined as indicated at H to the driven shaft 23 and an annular element I2 which is in turn splined to the element Ill. The splined connection between the elements II and I2 comprises internal teeth I4 on the latter and external teeth 15 on the former, the teeth 14 being also adapted for selective meshing rela tion with the teeth of the clutch portions I. and 2| of the adjacent gears l5 and 22. A plurality of detents ll, urged radially outward by coil springs 18, are received in recesses 18 in segmental elements 8| which are supported in the peripheral portion of the element 10 for slight circumferential displacement with respect thereto. Thus the segmental elements may be secured, as shown in detail in Figure 12, to annular elements 83, the latter being provided with inwardly directed radial flanges 84 which engage the lateral faces of the element 10, sufilcient clearancebeing provided to permit the necessary relative circumferential displacement of the annular elements 83, which together with the segmental elements 8i form a unitary structure, and the element 10. It will beobserved that the teeth I! on the element 10 are arranged in groups which are circumferentially spaced about the periphery of the element, the latter being recessed as indicated at 85 intermediate these groups of teeth to receive the segmental elements 8|. The extent of relative circumferential movement of the elements 10 and 82 is thus determined by the clearance between the segmental elements BI and the generally radial walls of the recesses 05. The detents 11 are arranged to engage in shallow recesses 86 formed in certain only of the teeth 14 in the median plane of the element 12. If desired, these recesses 26 may be formed in all of the teeth 14 to simplify assembly of the elements I 10 and 12, but this is of course not necessarysince these elements may be so assembled that those teeth provided with recesses may overlie the detents 11.

The cooperating members'of the synchronizing clutch acting between the gears II and 22 and ment by the adjacent one of two clutch rings 81, 1

Position within the annular elements 88 and being scored or grooved if desired.

It will be observed from Figure 9 that each of the detents I1 is provided adjacent its inner end with a generally conical surface 88 and that each of the coil springs 18 is seated in a recess II in the element III, the outer ends of the recesses 8i being flared'to provide surfaces 82 of generally conical shape which are complementary to the surfaces 88. The recesses 8i are so shaped that when the member 12 is slid either to the right or the left from the position in which it isshown in Figure 9, for example, by manipulation of a shifter fork 42 or the like, and the detents I1 are accordingly forced inwardly, these detents may move freely into the recesses 8|. However, if the annular elements 83 are displaced circumferentially with respect to the element 18, the detents 11 are retained in their outer position in which they are shown in Figure 9 by reason of the engagement of the conical surfaces 88 and 82. Such circumferential displacement occurs during synchronization prior to positive clutching as the result of the application of torque to the elements 88 by the action of the synchronizing clutch.

In the operation of the device, if it be desired to clutch the gear l to the shaft 28, the element I2 is displaced to the left and carries with it the element 18 by reason of the yielding connection between these elements afforded by the detents 11. The clutch ring 81 is thus caused to engage the adjacent annulus 88 and if the shaft 28 and gear l5 are rotating at different speeds, the elements 88 are circumferentially displaced with respect to the element 18. Continued displacement of the element 12 to the left is thus either rendered diflicult'or entirely prevented by the engagement of the conical detent surfaces 88 with the complementarysurfaces 82. As the element 12 and gear I5 approach synchronous rotation, the applied torque which tends to maintain the elements 88 in circumferentially displaced position with respect to the element 18, is gradually decreased. When a condition of approximate synchronism is establishecL the element '2 may be readily displaced further toward the left, the detents I1 being forced inwardly and into the recesses 8i, and proper meshing'engagement may thus be effected between the element 12 and the clutch portion l6 of the gear IS. The operation of clutching the gear 22 to the shaft 28 is carried out in the same manner by displacement of the element I2 to the right.

Figure 13 illustrates the application of the invention to a gear train of the so-called slidable gear type, in which two gears are relatively displaced into intermeshing relation for the purpose of establishing the drive or selecting a given ratio. Thus it is here desired to move an annular element 82', having a toothed portion 88, into meshing relation with a gear 81 and to establish prior to the engagement of the toothed elements a relative rotational speed such that the meshing may be effected without difficulty and with a minimum of noise. To this end the annular element 32 is splined to an element 38', which is in turn spllned to the shaft 23'. A gear 22 meshes with the gear 81 and is provided with a laterally directed annulus 55 formed to provide a clutch surface with which a complementary clutch surface on the element 38 may engage. The construction and mode of operation are otherwise quite similar to that described in connection with the remaining figures of the drawings, the frictional engagement being established prior to the engagement of the toothed portion 88 of the annulus 82! with the gear 81, so that the latter is brought up to the proper speed by the gear 28' which has the same number of teeth as-the toothed portion 88.

It will be appreciated that in its broader aspect the invention contemplates means whereby any two rotatable torque transmitting elements may be positively connected, which means may be freely operated to eflect such positive connection only after a condition of approximate synchronism of the two elements has been established.

Having thus described the invention, what is claimed as new and desired to besecured by Letters Patent is:

1. In a motor vehicle transmission having driving and driven members, positive clutch means slidable to connect said members, a friction clutch between said members engageable in advance of the positive clutch means, yielding means connecting said positive clutch means and said friction clutch to effect engagement of the latter during sliding of the former, and means operable on engagement of said friction clutch and prior to the establishment of approximate synchronous movement of said members for retarding further sliding of said positive clutch means in a direction to positively connect said members, said last named means acting on said yielding means. I

2. In apparatus of the class described. the combination with, coaxial rotating elements, of means including a member displaceable axially for effecting positive coupling between said elements, means including a. member displaceable axially for effecting frictional coupling between said elements, a releasable connection between said members including a spring detent, .whereby said frictional coupling may be established by axial displacement of said first named member and prior to the establishment of said positive coupling, and means operable by said frictional coupling, eil'ectlve while said elements are rotating at different speeds, and acting on said detent to oppose release of the latter, whereby establishment of said positive coupling is opposed until said elements are rotating in substantial synchronism.

3. In clutch synchronizing apparatus, the combination with an axially movable positive clutch member, of a friction clutch member, spring detent means releasably coupling said members for initial concurrent axial displacement to render said friction clutch member effective prior to said positive clutch member, and means movable circumferentially with respect to said spring detent means on initial engagement of said frictionclutch member for engaging said spring detent means and opposing release thereof until synchronization is effected.

4. In clutch synchronizing apparatus, thecombination with an axially movable positive clutch member, of a friction clutch member, spring detent means releasably coupling said members for initial concurrent axial displacement to render said friction clutch member effective prior to said positive clutch member, and means movable circumferentially with respect to said spring detent means on initial engagement of said friction clutch member for opposing release of the coupling between said members until synchronization is effected, said last named means having a cam surface for engagement with a cooperating cam surface on said spring detent means to resist displacement of the latter.

5. In apparatus of the class described, the combination with coaxial rotating elements, of means including a member displaceable axially for eflecting positive coupling between said elements, means including a member displaceable axially through a less distance for efiecting frictional coupling between said elements, a releasable connection between said members, whereby said members may together be displaced axially to eflect frictional coupling between said elements prior to the establishment of positive connection therebetween, and means responsive to differing rotational speeds oiv said elements and acting on said releasable connection, to resistrelease of the latter.

' latter.

prior to the establishment of positive connection therebetween, and means operable by said irictional coupling, effective only while said elements are rotating at diflerent speeds, and acting on said releasable coupling to resist release of the WALTER a. Gmswom. 

